System and method for bottom coating food products

ABSTRACT

A product conveying and coating system includes at least first and second, sequentially arranged conveyor belts, with at least the second conveyor belt being a solid belt. Interposed in a gap between the first and second belts is a dispenser head of a coating manifold. The dispenser head spans a gap between upper surface portions of the first and second conveyor belts, with an elongated side wall outlet portion of the dispenser head being exposed, in a downstream direction of the conveyor unit, to the upper surface of the second conveyor belt. The system provides for dispensing of coating material directly onto the second, solid conveyor belt and enrobing at least bottom and partial side portions of food products upon the solid belt. Provisions are made for scraping from the solid belt, removing from the food products and recycling excess coating material.

FIELD OF THE INVENTION

The invention pertains to the art of coating food products and, more specifically, to a system and method of coating bottom portions of food products conveyed upon a solid belt.

BACKGROUND OF THE INVENTION

In the manufacturing of certain food products, it is sometimes desired to provide a surface coating on the food products. For instance, topical coatings are quite common on a wide range of food products. The overall coating process can significantly vary, particularly depending on the coating material being employed and the food product surfaces to be coated. For instance, in the case of topical coatings, whether in particulate or liquid form, it is common to provide a feed hopper or other dispenser above the food product as the product moves along a conveyor. In such an arrangement, the conveyor belt is generally formed of interconnected metal wires or links which enables most of the excess coating material to fall or flow through the conveyor belt and collected for reuse. If it is desired to coat the bottom and even sides of a food product, the conveyor belt can be directed into a container of the coating material, essentially dipping the food product and mesh conveyor belt in the coating material. In the art, this type of coating system which enables coating of multiple surfaces of a food product is often referred to as an enrober.

Known enrobers are considered to be quite expensive and complicated. In addition, in the food industry, the conveyors must be cleaned at regular intervals, which can be important for various reasons including allergins. At least in the case of liquid coating enrobers, cleaning the links of the conveyor is extremely difficult and time consuming. By way of example, in the range of twenty to thirty-five hours of man-time is often required to clean an open mesh conveyor of an enrober system used to apply chocolate to the bottom of chewy grain bars. Obviously, this represents a significant amount of downtime for a production line.

SUMMARY OF THE INVENTION

The invention is directed to a system and method for enrobing at least bottom and partial side portions of food products by utilizing a conveyor unit employing a solid belt at a coating station. More specifically, the invention provides for a product conveying system including at least first and second, sequentially arranged conveyor belts, with at least the second conveyor belt being constituted by a solid belt. Interposed in a gap between the first and second belts is a dispenser head of a coating manifold. An upper surface of the second conveyor belt is arranged in a plane just below a plane of an upper surface of the first conveyor belt such that the dispenser head spans the gap, with an elongated outlet portion of the dispenser head being exposed, in a downstream direction of the system, to an upper surface of the second conveyor belt.

During operation, the manifold receives a liquid coating material and dispenses the coating material directly onto a predetermined percentage of the overall width of the second, solid belt while spaced food products are directed from the first belt into the coating material on the second belt. In accordance with an aspect of the invention, the coating material is thick so as to not readily flow off the belt, thereby avoiding the need for any lateral containment structure on the solid belt. With this arrangement, the coating material coats the bottom or lowermost side of the food product, as well as extending up and coating side portions of the food product to a degree dependent upon the food product being coated and the coating thickness or height applied to the solid belt. Downstream of the dispenser head, the coated food product is removed from the solid belt and the excess coating material is scraped from the belt, collected, filtered and recycled back to the manifold.

In accordance with a particular embodiment of the invention, the coating material is thick, melted chocolate which is applied onto the solid belt with a low pressure drop (e.g., less than 0.1 psig) across the horizontal portion of the head and a higher pressure drop (e.g., preferably in the range of 2-30 psig and, more preferably, 7-12 psig) across the vertical portion of the dispenser head to provide a uniform layer thickness across the belt. The layer thickness depends on the desired coating weight and is preferably about 6-9 mm for bottom coating chewy grain bars and 2-5 mm for bottom coating of crunchy baked bars. Layer thickness is primarily varied by how much coating is applied to the belt. Upon reaching a downstream end of the second belt, the coated bars are automatically transferred onto a third conveyor belt which is also solid and constitutes a cooling or chill belt, establishing a predetermined cooling temperature and residence time. Still, the invention has applicability to a wide range of coatings and products, basically coating materials which can be heated and cooled to alter viscous characteristics thereof and food products which can be sheeted and conveyed. In any case, additional objects, features and advantages of the invention will become more readily apparent from the following detailed description when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a food product coating and conveying system according to an embodiment of the invention.

FIG. 2 is an enlarged perspective view of a portion of the system of FIG. 1.

FIG. 3 is an enlarged view of a corner section of a tap-down roller unit employed in connection with an aspect of the invention.

FIG. 4 is a perspective view of a terminal end of one conveyor section provided in the system of FIG. 1.

FIG. 5 is a perspective view detailing another portion of the system of FIG. 1.

DETAILED DESCRIPTION OF INVENTION

With initial reference to FIG. 1, a coating system constructed in accordance with the present invention is generally indicated at 2. Coating system 2 incorporates a transfer station 6 including a first conveyor unit 9 employing a first conveyor belt 12 shown as an endless, solid belt. In the position illustrated, conveyor belt 12 has a first longitudinal end 16 which extends about a roller 17 and leads to a downstream, second longitudinal end 18 which is also supported by a roller (not shown). Between first and second longitudinal ends 16 and 18 is established an upper surface 21 of conveyor belt 12. Stemming from second longitudinal end 18 is a down-turned portion 27 which extends about a drive roller 29 of a drive unit 32. At this point, it should be noted that drive roller 29 can be rotatably driven in various ways to propel conveyor belt 12. For instance, drive unit 32 can itself constitute an electric, hydraulic or other motor or, as in the illustrated embodiment, drive unit 32 can include a pulley 34 which is adapted to be driven by a further drive belt/motor drive mechanism (not shown). In any case, from drive roller 29, conveyor belt 12 has an upturned portion leading back to first longitudinal end 16. At this point, it should be apparent that the drawings presented here show simplified conveyor arrangements for reference purposes only. Therefore, it should be understood that idler pulleys, tracking systems, take-up adjustment mechanisms and the like as commonly known in the art would also be employed.

As will become more fully evident below, the present invention can be used in coating bottom and partial side portions of various products. In one particular embodiment, coating system 2 is used in coat food products 45 in the form of chewy grain bars, each having a bottom surface 47, a front side surface 48, a rear side surface 49, lateral side surfaces 50 and 51, and a top surface 52. As shown, the previously prepared food products 45 have been deposited on upper surface 21 in rows and columns for transport by conveyor belt 12 from transfer station 6 to a downstream coating station 55. Coating station 55 includes a second conveyor unit 59 employing a second conveyor belt 63 having, in the position illustrated, a first longitudinal end 66 supported by a roller 67 and a second longitudinal end 68 supported by a roller 69, with conveyor belt 63 establishing an upper surface 73 between first and second longitudinal ends 66 and 68. From upper surface 73, conveyor belt 63 leads to a down-turned portion 76 extending around a drive roller 79 of a drive unit 82, which may include a pulley 84 such as for a common drive with drive unit 32, and an upturned portion 88 leading back to first longitudinal end 66.

For reasons which will be more fully detailed below, it is important in accordance with the present invention that second conveyor belt 63 is constituted by a solid conveyor belt, without any associated open mesh metal wires or links. In the embodiment shown, conveyor belt 63 is formed entirely from a polymeric material, such as a polyester base provided with a polyurethane topcoat. That is, in order to not depart from the invention, conveyor belt 63 must be solid, at least across a majority of the lateral dimension or width of conveyor belt 63. However, prior to further detailing this important aspect of the invention, FIG. 1 also illustrates a cooling station 105 as part of coating system 2. As shown, cooling station 105 includes a frame 107 supporting a third conveyor unit 110. Third conveyor unit 110 includes a third conveyor belt 113 shown having a first longitudinal end 116. Conveyor belt 113 is also shown to include an upper surface 123, a return portion 126 extending about a guide roller 129 and a drive roller 132 of a drive unit 135 having a pulley 137, and an upturned portion 140 leading back to first longitudinal end 116. In order to establish a desired cooling function, cooling station 105 includes at least one chiller unit, such as indicated at 144, for cooling conveyor belt 113. In general, chiller unit 144 can take various forms, including employing conduction and/or convection cooling arrangements, with one preferred embodiment employing a chip plate cooler provided directly below conveyor belt 113.

As best shown in FIG. 2, a vertical and longitudinal gap 151 is established between second longitudinal end 18 of first conveyor belt 12 and first longitudinal end 66 of second conveyor belt 63. Interposed in gap 151 is a coating unit 153. More specifically, coating unit 153 includes a manifold 157, having an input port 160, and an upstanding dispenser head 164. As clearly illustrated, it is dispenser head 164 which projects into gap 151, with dispenser head 164 including an uppermost wall 169, an upstream side wall 170 and a downstream side wall 171. In downstream side wall 171 and effectively extending across a majority of the lateral dimension or width of second conveyor belt 63 is at least one elongated dispensing opening or outlet 175 for dispensing a coating material 180 onto upper surface 73. More specifically, upper surface 21 of first conveyor belt 12 is located in a plane above a plane established by upper surface 73 of second conveyor belt 63. Therefore, upper surface 73 is just below upper surface 21. On the other hand, uppermost wall 169 of dispenser head 164 is substantially flush with upper surface 21, while dispensing opening 175 has a lowermost edge (not separately labeled) which is substantially coplanar with upper surface 73, and an uppermost edge (also not labeled). With this arrangement, dispenser head 164 spans gap 151, with elongated outlet opening 175 of dispenser head 164 being exposed, in a downstream direction of conveyor unit 9, to upper surface 73 of second conveyor belt 63 such that coating material 180 having a predetermined thickness (height) can be directly deposited upon upper surface 73 of second conveyor belt 63 from a position between first and second conveyor belts 12 and 63.

Prior to describing the overall operation of coating system 2, further structure associated with the present invention will now be described in connection with the illustrated embodiment. Initially, as shown in FIGS. 1 and 3, coating system 2 can employ a tap-down or presser unit 188 for forcing food products 45 into coating material 180 upon second conveyor belt 63. In the embodiment shown, presser unit 188 includes a pair of side support brackets 191 and 192 which support a transverse shaft 194. Adjustably secured to shaft 194 is a lock collar 196 which defines a stop surface 198. Presser unit 188 also includes a sleeve member 203 extending about and rotatably supported by shaft 194, with sleeve member 203 defining an abutment 206 aligned with stop surface 198. In addition, at spaced locations along shaft 194, presser unit 188 includes radial flanges 210, which extend from and are fixed to sleeve member 203 for rotation relative to shaft 194, and support rings 214 fixed to radial flanges 210. Each support ring 214 adjustably receives a respective support rod 224, 225. Support rods 224 and 225 terminate in support plates 228 and 229 which rotatably support a roller 233 having an outer sheath 236. With this arrangement, sheath 236 engages the top surface 52 of each food product 45 as second conveyor belt 63 is driven, thereby forcing the food products 45 to be partially immersed in coating material 180. The engagement of abutment 206 with stop surface 198 limits the degree to which roller 233 can shift downward. Although roller 233 could be biased in this direction, it has been found that the mere weight of this structure provides sufficient force for this function. The vertical distance between roller 233 and upper surface 73 of second conveyor belt 63 can be readily adjusted by securing lock collar 196 to shaft 194 at a select location, such as with a set screw (not shown). Roller 233 can be freely, rotatably supported by support plates 228 and 229, but roller 233 can also be positively driven to rotate in unison with the movement of second conveyor belt 63, such as by employing a self-contained drive motor (not shown) within the structure of roller 233.

FIGS. 1 and 4 illustrate the inclusion of a hopper 253 used to hold coating material 180. More specifically, as best illustrated in FIG. 4, hopper 253 is shown to be supported by legs 256-259 (not depicted in FIG. 1 for clarity of the drawing) and includes an outlet port 262. Hopper 253 is positioned below upper surface 73 of second conveyor belt 63 and has associated therewith a scraper device 265 including a blade member 268 having an edge 270 which engages inturned portion 176 of second conveyor belt 63. With this arrangement, scraper device 265 is located at a position spaced from second longitudinal end 68 and below upper surface 73 of second conveyor belt 63. At this location, the excess coating material 180 is scraped from second conveyor belt 63 and collected in hopper 253, enabling the coating material 180 to be pumped through outlet port 262, filtered and recycled back to manifold 157 through additional pumping and filtering equipment (not shown).

FIGS. 1 and 5 will now be referenced in describing a spinner device 276 also incorporated into coating system 2. As shown, spinner device 276 includes a spinner bar 280 which is rotatably supported by a support block 284 at one end and a support plate 287 at another end. A drive motor 290 is employed to rotate spinner bar 280. With this overall arrangement, the food products 45 deposited on first conveyor belt 12, which actually can be made of solid or mesh construction, are transferred above uppermost wall 169 of dispenser head 164 onto coating material 180 already deposited upon upper surface 73 of second, solid conveyor belt 63. Although coating material 180 and the thickness (height) thereof can vary in accordance with the invention, one embodiment employs about a 8-9 mm layer of thick chocolate having a molasses-like consistency being delivered through an approximately 7.5 cm delivery pipe (not shown) connected to inlet port 160 of manifold 157 at a temperature in the range of 35-46° C. (about 95-115° F.). Importantly, the solid construction of conveyor belt 73 is such that coating material 180 will not flow through upper surface 73. At the same time, coating material 180 is thick, i.e., has a high viscosity, such that coating material 180 must be pumped for dispensing and will not flow laterally off of upper surface 73. For dispensing the coating material 180, upstanding dispenser head 164 is designed such that there is a very low pressure drop across the width, but rather the majority of the pressure drop occurs over the height.

In accordance with a particular embodiment of the invention, the coating material is thick, melted chocolate which is applied onto the solid belt with a low pressure drop (e.g., less than 0.1 psig) across the horizontal portion (not separately labeled) of dispenser head 164 and a higher pressure drop (e.g., preferably in the range of 2-30 psig and, more preferably, 7-12 psig) across the vertical portion (not separately labeled) of dispenser head 164. This assures an even flow, with food products 45 becoming partially immersed in coating material 180 such that coating material 180 will become enrobed on at least bottom surface 47 and portions of front, rear and side surfaces 48-51. The layer thickness depends on the desired coating weight and is preferably 6-9 mm for bottom coating chewy grain bars and 2-5 mm for bottom coating of crunchy baked bars. At the same time, presser unit 188 can further assure that an appropriate tap-down force is applied on food products 45 for proper coating. Once reaching second longitudinal end 68, the coated food products 298 are transferred onto third conveyor belt 113 of cooling station 105, while excess coating material 180 is delivered into hopper 253 in conjunction with scraper device 265. Any tailing of the coating material 180 associated with the transfer to cooling station 105 is avoided by the presence of spinner device 276.

The length of first conveyor unit 9 will depend on the overall manufacturing configuration. On the other hand, the length of second conveyor unit 59 can actually be quite short, such as less than 2 meters, along with a preferably commensurate width. The length of third conveyor unit 110 will depend on the time need to cool and further solidify coating material 180. In the case of chocolate, a rather long cooling period is typically needed, such as about a 3 minute residence time. With this in mind, this length can be from 12-25 meters, but can be advantageously reduced to about 3 meters utilizing certain conveyor material and a flat, aluminum plate cooling system. To this end, a thin, high heat transfer material, such as TEFLON, having a thickness in the order of about 0.025 cm (10/1000 of an inch) can be advantageously employed as the conveyor material such that this overall chilling arrangement can reduce the cooling time to approximately 40 seconds.

Although described with reference to exemplary embodiments of the invention, it should be readily understood that various changes and/or modifications can be made to the invention without departing from the spirit thereof. For instance, other than applying chocolate, various other coating materials which can be heated and cooled could be employed, including yogurt, marshmallow, fruit and cheese. In addition, other food products which can be sheeted and conveyed could be coated, including candy, dough, cereal, cookies and ice cream. Most importantly, it has been found that completely avoiding mesh metal conveyor materials but rather utilizing the solid and small length (less surface area) conveyor belt as discussed above for the coating operation enables the cleaning time to be significantly reduced, basically from about thirty-five hours to about four hours, thereby representing a major efficiency enhancement. 

I claim:
 1. A method of coating bottom and partial side portions of a food product comprising: directing the food product in a longitudinal direction along a first conveyor belt which is longitudinally spaced from a second, solid conveyor belt by a longitudinal gap extending in the longitudinal direction; dispensing a coating material onto and laterally across a portion of the second, solid conveyor belt from a dispenser head positioned within the longitudinal gap, with the dispenser head including an uppermost wall, an upstream side wall, a downstream side wall and at least one dispensing opening provided in the downstream side wall, while being above and exposed to an upper surface of the second, solid conveyor belt for horizontally dispensing of the coating material; transferring the food product from upon the first conveyor belt directly onto the second, solid conveyor belt wherein the food product becomes partially immersed in the coating material to establish a coated food product; and removing the coated food product from the second, solid conveyor belt.
 2. The method of claim 1, further comprising: pumping the coating material to the dispenser head through a manifold.
 3. The method of claim 2, further comprising: collecting excess coating material from the second, solid conveyor belt and recycling the excess coating material to the manifold.
 4. The method of claim 3, wherein collecting the excess coating material includes scraping the excess coating material from the second, solid conveyor belt.
 5. The method of claim 1, further comprising: forcibly pressing the food product into the coating material upon the second, solid conveyor belt.
 6. The method of claim 1, wherein delivering the coating material across a portion of the second, solid conveyor belt constitutes delivering the coating material across a majority of the second, solid conveyor belt.
 7. The method of claim 6, wherein the coating material is thick such that, upon dispensing the coating material onto and laterally across the majority of the second, solid conveyor belt, the coating material does not flow laterally off the second, solid conveyor belt.
 8. The method of claim 1, wherein removing the coated food product from the second, solid conveyor belt includes transferring the coated food product to a third conveyor belt which is longitudinally aligned with the second, solid conveyor belt, said method further comprising chilling the coated food product on the third conveyor belt.
 9. The method of claim 1, wherein the food product constitutes a chewy grain bar and the coating material constitutes chocolate.
 10. A system for coating bottom and partial side portions of a food product comprising: a first conveyor belt, said first conveyor belt being configured to deliver a food product in a longitudinal direction; a second, solid conveyor belt longitudinally spaced from the first conveyor belt by a longitudinal gap extending in the longitudinal direction; and a dispenser head positioned within the longitudinal gap and including at least one dispensing opening exposed to an upper surface of the second, solid conveyor belt, wherein coating material is configured to be dispensed from the dispenser head onto and laterally across a portion of the second, solid conveyor belt from within the longitudinal gap such that food product delivered upon the first conveyor belt being transferred directly onto the second, solid conveyor belt and become partially immersed in the coating material in order to establish a coated food product, wherein the dispenser head includes an uppermost wall, an upstream side wall and a downstream side wall, said uppermost wall being above an upper surface of the second, solid conveyor belt, with the at least one dispensing opening being provided in the downstream side wall for horizontally dispensing of the coating material.
 11. The system according to claim 10, wherein the uppermost wall of the dispenser head is substantially flush with an upper surface of the first conveyor belt.
 12. The system according to claim 10, further comprising a manifold for the coating material, said dispenser head projecting from the manifold.
 13. The system according to claim 12, wherein the second, solid conveyor belt includes a first longitudinal end juxtapose the gap and a second longitudinal end, said system further comprising a scraper device for removing excess coating material from the second, solid conveyor belt and a hopper for collecting the excess coating material, said scraper device being located at a position spaced from the second longitudinal end and below the upper surface of the second, solid conveyor belt.
 14. The system according to claim 10, further comprising: a presser unit mounted above the upper surface of the second, solid conveyor belt for forcibly pressing the food product into the coating material upon the second, solid conveyor belt.
 15. The system according to claim 14, wherein the presser unit includes a roller extending laterally across the second, solid conveyor belt and means for adjusting a height of the roller above the upper surface of the second, solid conveyor belt.
 16. The system according to claim 10, wherein the second, solid conveyor belt includes a first longitudinal end juxtapose the gap and a second longitudinal end, said system further comprising a spinner bar provided at the second longitudinal end for removing excess coating material from the food product.
 17. The system according to claim 10, further comprising: a third conveyor belt which is longitudinally aligned with the second, solid conveyor belt downstream of the first conveyor belt, said third conveyor belt constituting a chiller belt for chilling the coated food product on the third conveyor belt.
 18. The system according to claim 17, wherein each of the first and third belts are also constituted by solid belts such that the system is void of any open mesh belts.
 19. A system for coating bottom and partial side portions of a food product comprising: a first conveyor belt, said first conveyor belt being configured to deliver a food product in a longitudinal direction; a second, solid conveyor belt aligned with and longitudinally spaced from the first conveyor belt by a longitudinal gap extending in the longitudinal direction; and a dispenser head including an uppermost wall entirely positioned within the longitudinal gap substantially flush with an upper surface of the first conveyor belt and above an upper surface of the second, solid conveyor belt and including at least one dispensing opening exposed to an upper surface of the second, solid conveyor belt, wherein coating material is configured to be horizontally dispensed from the dispenser head onto and laterally across a portion of the second, solid conveyor belt from within the longitudinal gap such that food product delivered upon the first conveyor belt being transferred across the uppermost wall of the dispenser head and onto the second, solid conveyor belt and become partially immersed in the coating material in order to establish a coated food product. 